Ranging device, ranging method, signal processing device, and light projecting device

Abstract

A ranging device provided with a light projecting unit for projecting a reference pulse set row including a main pulse and at least one sub pulse, a light receiving unit for receiving a reflected pulse set row obtained by reflection of the reference pulse set row by an object to be measured, and an identifying unit for identifying the reflected pulse set row corresponding to the reference pulse set row. The ranging device is further provided with a calculating unit for calculating a distance to the object to be measured on the basis of a delay time difference between the reference pulse set row and the reflected pulse set row corresponding to the reference pulse set row. The light projecting unit projects a plurality of reference pulse set rows having different pulse intervals.

The invention claimed is: 
     
       1. A ranging device, comprising:
 a light projecting unit configured to project a plurality of reference pulse set rows on an object, wherein
 each reference pulse set row of the plurality of reference pulse set rows includes a main pulse and at least one sub pulse, and 
 a first pulse interval between the main pulse and the at least one sub pulse of a first reference pulse set row of the plurality of reference pulse set rows is different from a second pulse interval between the main pulse and the at least one sub pulse of a second reference pulse set row of the plurality of reference pulse set rows; 
 
 a first light receiving unit configured to receive a reflected pulse set row obtained by reflection of the first reference pulse set row by the object; 
 an identifying unit configured to identify the reflected pulse set row corresponding to the first reference pulse set row; 
 a calculating unit configured to calculate a distance to the object based on a delay time difference between the first reference pulse set row and the reflected pulse set row; and 
 an error detecting unit configured to determine a presence of an error in the calculated distance,
 wherein the light projecting unit is further configured to change the first pulse interval and the second pulse interval based on the determination of the presence of the error in the calculated distance. 
 
 
     
     
       2. The ranging device according to  claim 1 , further comprising a second light receiving unit configured to receive the first reference pulse set row projected from the light projecting unit. 
     
     
       3. The ranging device according to  claim 2 , further comprising:
 a first clocking unit configured to obtain a timing at which the reflected pulse set row is received by the first light receiving unit; and 
 a second clocking unit configured to obtain a timing at which the first reference pulse set row is received by the second light receiving unit. 
 
     
     
       4. The ranging device according to  claim 1 , further comprising a storage unit configured to store the first pulse interval and the second pulse interval,
 wherein the identifying unit is further configured to:
 refer to the stored first pulse interval; and 
 identify, based on the referred first pulse interval, the reflected pulse set row corresponding to the first reference pulse set row. 
 
 
     
     
       5. The ranging device according to  claim 1 , wherein each of the first pulse interval and the second pulse interval is variable. 
     
     
       6. The ranging device according to  claim 1 , wherein the light projecting unit includes a control unit configured to supply information indicating the first pulse interval and the second pulse interval to the identifying unit. 
     
     
       7. A ranging method, comprising:
 projecting, by a light projecting unit, a plurality of reference pulse set rows on an object, wherein
 each reference pulse set row of the plurality of reference pulse set rows includes a main pulse and at least one sub pulse, and 
 a first pulse interval between the main pulse and the at least one sub pulse of a first reference pulse set row of the plurality of reference pulse set rows is different from a second pulse interval between the main pulse and the at least one sub pulse of a second reference pulse set row of the plurality of reference pulse set rows; 
 
 receiving, by a light receiving unit, a reflected pulse set row obtained by reflection of the first reference pulse set row by the object; 
 identifying, by an identifying unit, the reflected pulse set row corresponding to the first reference pulse set row; 
 calculating, by a calculating unit, a distance to the object based on a delay time difference between the first reference pulse set row and the reflected pulse set row; 
 determining, by an error detecting unit, a presence of an error in the calculated distance; and 
 changing, by the light projecting unit, the first pulse interval and the second pulse interval based on the determination of the presence of the error in the calculated distance. 
 
     
     
       8. A signal processing device, comprising:
 a light receiving unit configured to receive a reflected pulse set row obtained by reflection of a first reference pulse set row of a plurality of reference pulse set rows by an object, wherein
 each reference pulse set row of the plurality of reference pulse set rows includes a main pulse and at least one sub pulse, and 
 a first pulse interval between the main pulse and the at least one sub pulse of the first reference pulse set row is different from a second pulse interval between the main pulse and the at least one sub pulse of a second reference pulse set row of the plurality of reference pulse set rows; 
 
 an identifying unit configured to identify the reflected pulse set row corresponding to the first reference pulse set row; 
 a calculating unit configured to calculate a distance to the object based on a delay time difference between the first reference pulse set row and the reflected pulse set row; and 
 an error detecting unit configured to:
 determine a presence of an error in the calculated distance; and 
 output, to a light projecting device, a result indicating the presence of the error in the calculated distance,
 wherein the light projecting device changes the first pulse interval and the second pulse interval based on the result indicating the presence of the error in the calculated distance. 
 
 
 
     
     
       9. A light projecting device, comprising:
 a light projecting unit configured to project a plurality of reference pulse set rows on an object, wherein
 each reference pulse set row of the plurality of reference pulse set rows includes a main pulse and at least one sub pulse, and 
 a first pulse interval between the main pulse and the at least one sub pulse of a first reference pulse set row of the plurality of reference pulse set rows is different from a second pulse interval between the main pulse and the at least one sub pulse of a second reference pulse set row of the plurality of reference pulse set rows; and 
 
 a control unit configured to receive a result from a specific device, wherein
 the specific device calculates a distance to the object, 
 the result indicates a presence of an error in the calculated distance, and 
 the light projecting unit is further configured to change the first pulse interval and the second pulse interval based on the result indicating the presence of the error in the calculated distance.